The present invention is directed generally to data communication. More particularly, the present invention relates to methods and arrangements for transferring data between two busses. The invention is exemplified using an application involving the design of semiconductors and their validation using an extended reference-chip development platform.
The electronics industry continues to strive for high-powered, high-functioning circuits. Significant achievements in this regard have been realized through the fabrication of very large-scale integration of circuits on small areas of silicon wafer. Integrated circuits of this type are developed through a series of steps carried out in a particular order. The main objective in designing such devices is to obtain a device that conforms to geographical features of a particular design for the device. To obtain this objective, steps in the designing process are closely controlled to insure that rigid requirements are realized.
Semiconductor devices are used in large numbers to construct most modern electronic devices. In order to increase the capability of such electronic devices, it is necessary to integrate even larger numbers of such devices into a single silicon wafer. As the semiconductor devices are scaled down (i.e., made smaller) to form a larger number of devices on a given surface area, the structure of the devices and the fabrication techniques used to make such devices have become more refined. This increased ability to refine such semiconductor devices has lead to an ever-increasing proliferation of customized chips, and with each chip serving a unique function and application. This, in tun, has lead to various techniques to design and successfully test chips efficiently and inexpensively.
For many chip designs, customized chips are made by describing their functionality using a hardware-description language (HDL), such as Verilog or VHDL. The hardware description is often written to characterize the design in terms of a set of functional macros. The design is computer simulated to ensure that the custom design criteria are satisfied. For highly-complex custom chip designs, the above process can be burdensome and costly. The highly integrated structure of such chips leads to unexpected problems, such as signal timing, noise-coupling and signal-level issues. Consequently, such complex custom chip designs involve extensive validation. This validation is generally performed at different stages using a Verilog or VHDL simulator. Once validated at this level, the Verilog or VHDL HDL code is synthesized, for example, using xe2x80x9cSynopsys,xe2x80x9d to a netlist that is supplied to an ASIC (Application Specific Integrated Circuit) foundry for prototype fabrication. The ASIC prototype is then tested in silicon. Even after such validation with the Verilog or VHDL simulator, unexpected problems are typical. Overcoming these problems involves more iterations of the above process, with testing and validation at both the simulation and prototype stages. Such repetition significantly increases the design time and cost to such a degree that this practice is often intolerable in today""s time-sensitive market.
Ways of improving the development of customized chips can lead to improved communication methods and arrangements that find use in a variety of applications. The present invention addresses the need to overcome the above-mentioned deficiencies of customized-chip development and also provides for communication methods and arrangements that are useful for other applications.
The present invention relates to a bus-interfacing circuit arrangement and method of data transferring in a manner that maximizes throughput. According to one application of the present invention in which the data transferring approach extends communication for a reference-chip development platform, the bus-interfacing circuit arrangement and method permits design efforts of ASIC devices to be significantly decreased in connection with design validation.
According to one embodiment, the present invention is directed to a method for passing data between a first bus on a reference chip and an external bus without using a bridge clocking protocol. The method comprises: coupling a two-way buffer arrangement between the external bus and the first bus; determining an initiating bus of the two-way buffer arrangement, wherein the initiating bus is the first bus on the reference chip if the data passing across the buffer arrangement is sourced by a device on the reference chip, and the initiating bus is the external bus if the data passing across the buffer arrangement is sourced by a device external to the reference chip; and in response to the determination, controlling the two-way buffer arrangement to asynchronously copy data through the two-way buffer arrangement from the initiating bus to the other one of the external bus and the first bus, wherein data is passed automatically in response to its presence at the buffer arrangement without any clock cycle delays.
According to another embodiment, the present invention is directed to an arrangement for passing data between a first bus on a reference chip and an external bus without using a bridge clocking protocol. The arrangement comprises: a two-way buffer arrangement between the external bus and the first bus; a logic circuit adapted to determine an initiating bus of the two-way buffer arrangement, wherein the initiating bus is the first bus on the reference chip if the data passing across the buffer arrangement is sourced by a device on the reference chip, and the initiating bus is the external bus if the data passing across the buffer arrangement is sourced by a device external to the reference chip; and wherein the logic circuit is further adapted to respond to the determination by controlling the two-way buffer arrangement to asynchronously copy data through the two-way buffer arrangement from the initiating bus to the other one of the external bus and the first bus, wherein data is passed automatically in response to its presence at the buffer arrangement without any clock cycle delays.
The above summary of the present invention is not intended to describe each illustrated embodiment or every implementation of the present invention. The figures and the detailed description that follow more particularly exemplify these embodiments.